The present invention relates to a helicopter toy which is stably or steady in a flying body at during accent and which particularly secures stability of the flying body during descending.
A conventional helicopter toy is disclosed a, for example, in Japanese Patent Provisional Publication No. SHO 61-29381. The flying unit comprises a flying body, a plurality of rotor blades mounted to the flying body for rotation about a rotational axis and for angular movement about their respective pivotal axes extending perpendicularly to the rotational axis, a power source for giving a rotational force to the rotor blades to climb the flying body, and means for decreasing angles of attack of the respective rotor blades when transmission of power from the power source to the rotor blades is released, to stabilize the flying body while descending.
The power source uses a rubber material, and the rotor blades are as formed as to be moved angularly about their respective pivotal axes, by releasing forces due to twisting of elastic elements to their respective positions where the angles of attack of the respective rotor blades are lost. When the rubber material that is the power source is twisted several times, such action is generated to contract the rubber material so that a cap member pulled by the contracting action forcibly moves the rotor blades about their respective pivotal axes against the biasing forces of the respective elastic elements to cause the rotor blades to obtain a lifting power.
When the twisting of the elastic element is lost, the rubber material is lengthened or elongated in its length so that the cap member is returned to its original position by a biasing force of a spring so that the rotation of the rotor blades about the rotational axis is made free, and the angles of attack of the respective rotor blades are lost.
As described previously, when the rubber material is twisted several times, the angles of attack are given respectively to the rotor blades in such a direction as to cause the rotor blades to obtain their lifting power. At this time, if the rotor blades are rotated about the rotational axis by the releasing force from the twisting of the rubber material, the flying body lifts and climbs until the twisting force of the rubber material is lost.
When the twisting force of the rubber material is lost, the angles of attack of the respective rotor blades are lost so that the flying body is oriented horizontally and the rotor blades continue to be rotated about the rotational axis under a free condition. Since the rotor blades are rotated about the rotational axis, balance of the flying body is taken so that the flying body descends while maintaining its stable posture during ascent.
However, the conventional model flying unit has the following drawbacks.
That is, in the model flying unit, the rotor blades are rotated at descending about the rotational axis only by inertia of the rotor blades. Accordingly, if the ascending height is of the order of, for example, four (4) to five (5) meters, the rotor blades continue to be rotated about the rotational axis by the inertia of the rotor blades until the flying body lands. If the releasing force of the rubber material is strengthened so that the flying body climbs up to a location over the aforesaid ascending height, for example, of the order to ten (10) meters, however, a descending time is lengthened so that the rotation of the rotor blades due to their inertia is suspended on the way. Thus, balance of the flying body is lost or broken upon the suspension in rotation of the rotor blades so that the flying body falls down.
As a result, the following drawbacks arise. That is, the flying body falls like a crash not the flying condition so that the flying body spoils the fun. Further, descending under the falling condition increases the descending speed to damage the flying body.